LYON, France, Oct. 26 (UPI) -- Bacon, hot dogs, corned beef and other types of processed red meat significantly increase the risk for developing cancer, and all types of red meat "probably" increase the risk as well, according to a new report from the World Health Organization.
The WHO's International Agency for Research on Cancer, or IARC, report is based on decades of research, though its conclusions were far from unanimous among members of the panel. The report also is expected to be controversial in Western countries, especially the United States, where red meat is a staple of most people's basic diet.
"These findings further support current public health recommendations to limit intake of meat," said Dr. Christopher Wild, director of the IARC, in a press release. "At the same time, red meat has nutritional value. Therefore, these results are important in enabling governments and international regulatory agencies to conduct risk assessments, in order to balance the risks and benefits of eating red meat and processed meat, and to provide the best possible dietary recommendations."
Red meat is defined by the IARC as any unprocessed mammalian muscle meat, such as beef, veal, pork, lamb, and goat, including meat sold minced or frozen. Processed red meats are defined as having been enhanced for flavor or preservation by methods that include salting, curing, fermentation, or smoking, among others.
The National Cattlemen's Beef Association, a meat industry group in the United States, said in a press release it was hard to reconcile the "weak associations in human studies" between beef and cancer with the WHO panel's vote to approve the report.
"Of more than 900 items IARC has reviewed [that may cause cancer], including coffee, sunlight and night shift work, they have found only one 'probably' does not cause cancer according to their classification system," said Dr. James Coughlin, a nutritional toxicologist with the NCBA.
The IARC reviewed more than 800 studies on the link between at least a dozen types of cancer and consumption of red meat or processed meat. The most influential studies considered by the panel were among larger groups of participants followed for longer periods of time.
Among other risk assessments, the researchers found as little as 50 grams of bacon per day -- less than two slices -- can increase risk for colorectal cancer by 18 percent. Eating 100 grams of red meat per day, or about half of an eight-ounce steak, can increase cancer risk by 17 percent, the researchers reported.
The potential for processed meat, as well as red meat, to cause or make worse a wide-ranging list of cancers, including colorectal, breast, prostate and bladder, has been acknowledged for several years. A study in June showed red meat can increase risk of death from prostate cancer by 2.5 times. Another study in 2008 found red meat and dairy products had the potential to promote growth in any type of cancer.
"This decision doesn't mean you need to stop eating any red and processed meat, but if you eat lots of it you may want to think about cutting down," Tim Key, a professor at the University of Oxford and researcher at Cancer Research UK, told the BBC. "Eating a bacon bap every once in a while isn't going to do much harm -- having a healthy diet is all about moderation."
IARC researchers found meat consumption ranges widely between countries and cultures -- some consume small amounts of meat on an irregular basis while others include some type of meat with every meal.
"For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed," said Kurt Straif, a section head at the IARC, told the New York Times. "In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance."
The WHO report is published in The Lancet.